Coating compositions which have been used heretofore have been primarily organic-solvent based compositions, typically containing high-solvent concentrations of 40-50% by weight or more. Use of such solvent-based coatings have caused in significant air pollution problems resulting from the evaporation of organic solvents into the atmosphere during cure.
One alternative to such solvent-based coatings that has been proposed is the use of "high solids" formulations. Theoretically, these proposed formulations would contain at least about 60% by volume solids, preferably at least about 85% by volume or higher, with the remainder being organic and/or water solvent. The term "solids" is used herein and in the appended-to claims to mean the portion of the composition which is not subject to evaporation during cure. The "solids" may or may not themselves be solid before cure. Typically, the "solids" in the described compositions include resins.
U.S. Pat. Nos. 3,384,586 and 3,492,231 disclose resinous compositions containing a polymeric resin such as a polyolefin, polyamide, acrylic, polystyrene, polysulfide, polyether, polyester, melamine resin, alkyd resin and the like in combination with a minor amount of a non-Newtonian colloidal disperse system comprising (1) solid metal-containing colloidal particles predispersed in (2) a dispersing medium and (3) as an essential third component at least one organic compound which is soluble in said dispersing medium, the molecules of said organic compound being characterized by a hydrophobic portion and at least one polar substituent.
U.S. Pat. Nos. 4,436,855 and 4,443,577 disclose urethane coating compositions containing minor amounts of non-Newtonian colloidal disperse systems comprising (1) solid metal-containing colloidal particles predispersed in (2) a disperse medium of at least one inert organic liquid and (3) as an essential third component at least one member selected from the class consisting of organic compounds which are substantially soluble in said disperse medium, the molecules of said organic compound being characterized by polar substituents and hydrophobic portions. The former patent relates to two-component urethane coating systems which further comprise an organic polyfunctional isocyanate and an acidic ester of a phosphoric acid. The latter patent relates to one-component moisture curable urethane coating compositions which further comprise an isocyanate-terminated prepolymer.
U.S. Pat. No. 4,425,466 discloses coating compositions containing a partially methylated partially methylolated melamine and a polyfunctional compound containing on average at least two functional groups per molecule selected from the group consisting of carboxy, hydroxy, primary and secondary amide and urethane. The reference indicates that the coating compositions are stable at ambient temperature and capable of fast cure response at relatively low curing temperatures.
Grease compositions comprising a major amount of a thixotropic grease-like composition consisting essentially of a nonvolatile diluent oil, an oil-soluble dispersing agent, and an alkaline earth metal carbonate, and a minor amount of a polymer are described in U.S. Pat. Nos. 3,671,012 and 3,661,622. In U.S. Pat. No. 3,565,672, a method of improving the resistance of metal to corrosion is described which utilizes a grease-like composition comprising a nonvolatile diluent, a dispersing agent and a basic alkaline earth metal component as a coating composition which is then painted with a conventional paint. Compositions comprising a mixture of microcrystalline wax, dispersing agent and an alkaline earth metal carbonate are described in U.S. Pat. No. 3,746,643. Optionally, the mixture can contain a minor amount of a nonvolatile diluent oil.
A material used for minimizing the viscosity change of a substrate with temperature is called a viscosity modifier, viscosity improver, viscosity index improver or VI improver. The words "viscosity index improver" or "VI improver" have traditionally been used as synonyms for the words viscosity modifier or viscosity improver. Although a few non-polymeric substances such as metallic soaps exhibit VI improving properties, the VI improvers most often used are oil-soluble organic polymers. These polymers include polyisobutylenes; polymethacrylates (i.e., copolymers of various chain length alkyl methacrylates); copolymers of ethylene and propylene; and polyacrylates (i.e., copolymers of various chain length alkyl acrylates).
In recent years, there has been developed a series of hydrogenated block copolymers of styrene and conjugated dienes such as isoprene which are useful in lubricating oils as VI improvers. The physical nature of these hydrogenated block copolymers is such that they are supplied commercially as baled material, crumbs or pellets, or as additive concentrates containing these copolymers. Additive concentrates of this type are commercially available from the Shell Chemical Company under the names Shellvis 40 VI Improver Concentrate and Shellvis 50 VI Improver Concentrate. Copolymers of these types are described in, e.g., U.S. Pat. Nos. 3,554,911; 3,688,125; 3,763,044; 3,965,019; and 4,036,910.